Locking capsule



April 28, 1970 R J, GRAHAM ETAL 3,508,678

LOCKING CAPSULE Filed April 29, 1968 www wmw vh m mw T w45 T ID d A Mg nmi.. LW

United States Patent O ABSTRACT OF THE DISCLOSURE An economical lockingcapsule is provided having telescopically joinable cap and body partsadapted to be .joined together in a mechanical part-lock position andalso, when more fully joined, in a fully locked position. The capsule,for packaging of medicaments and the like, is produced by thedip-molding technic on conventional automatic machinery and can beprinted, filled, etc., using standard equipment.

SUMMARY AND DETAILED DESCRIPTION This invention relates to hard shelllocking capsules of the type having a cap part and a body part adaptedto be telescopically joined together to provide a container forsubstances such as pharmaceutical preparations intended for oraladministration. More particularly, the invention relates to capsules ofthe kind described which can be manufactured, printed, filled and joinedon modern high-production machinery and can be locked in the closedposition, as desired, in a partial mechanical lock or in a morecompletely joined solid mechanical lock.

The conventional locking pharmaceutical capsules consist of a tubular orcylindrical cap part closed at one end with the opposite end open totelescopically receive a closely tting body part of like conformationhaving contacting inner surfaces which provide a locking action toprevent separation of the cap and body parts. In general, the knowntypes of locking capsules are constructed to provide both a temporarylock (sometimes referred to as a semi-lock or pre-lock) when partlyjoined and a more secure lock when more fully joined. One such type ofcapsule, for example, is known from British patent specification No.1,108,629 and Italian Patent No. 789,324. The prior art locking capsuleshave in general been satisfactory but some types have occasionallymalfunctioned or failed from time to time in finishing, distribution,etc. In particular, the cap and body parts have sometimes tended to popapart when joined on the production line; also, empty capsules in thepre-lock position prior to filling or subsequently, as in shipment tothe customer, have sometimes pulled apart especially in a case where thecap has been insufficiently advanced onto the body. Also, capsules inthe fully locked position have sometimes been known to pull apart andbecome separated due to severe vibration. Capsules of the friction locktype, that is capsules locked with the capsule walls under distortion,have been known to crack and fail, especially under excessive dryingconditions as when filled with hygroscopic powders or other desiccatingsubstances. The failures are not uncommon, especially during theprinting operation using equipment which calls for precise lengthcontrol of the pre-lock caspule. Separation failures are also likely tooccur during the iilling steps, particularly where, as in standardmachinery, the capsules are delivered from the supply hopper byoscillatory movements tending to cause the capsule parts to separate. Aseparated part undesirably can cause the magazine tube to be blocked, ora free cap, for instance,

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can seat on a joined capsule body and form a doublecap which may jam therectifying mechanism. Also, the loose part can crowd the filling ringchamber so that the intended body part does not seat properly in thelilling ring. As will be appreciated, each malfunction constitutes aneconomic loss whether of production time, during finishing,distribution, etc.

It is therefore an object of the present invention to provide a lockingcapsule of a novel type having an improved pre-lock construction foroptimum performance during finishing, distribution, etc.

It is also an object of the invention to provide an improved capsulehaving cooperating elements for the partial and complete locking of thebody and cap parts.

Still another object of the invention is to provide an improved capsulehaving pre-lock means assuring the partial joining of the capsule partsin a constant pre-determined len-gth.

Yet another object of the invention is to provide prelock means forcapsules which prevents or minimizes the occurrence of popping apart ofthe capsule parts as they are being assembled.

Other objects, features and advantages of the invention will be seen inthe following specification with reference to the accompanying drawingsin which:

FIGURE l is a side view of an assembled capsule according to theinvention;

FIGURE 2 is a section taken on axis line 2-2 of FIG- URE 1, of the upperpart of a capsule of the invention in a full lock position;

FIGURE 3 is a similar view in the pre-locked or partly closed position;

FIGURE 4 is a transverse section of a capsule taken on line 4 4 ofFIGURE l;

FIGURE 5 is a plan view in section of the indented pre-lock contour ofthe cap mold pin, the pin contour being covered over with a capsuleshell coating;

FIGURE 5a is a section of the pre-lock position of a capsule shown inmatching contact according to the invention with the groove of a capsulebody;

FIGURE 6 is an elevational view of the cap pin contour represented inFIGURE 5; and

FIGURES 7a, 7b and 7c are sectional views illustrating the stepwisemigration of the capsule liquid onto the shaped contours of a capsulemold pin as the pin is dipped increasingly deeper into the capsuleliquid.

Referring to FIGURE l, the capsule of the invention 10 includes a cap 11and a body 12 with closed ends 13 and 14, the parts being readilymolded, stripped, etc., on standard capsule-making machinery andassembled easily, as desired, in either locked or semi-locked position.The cap 11 in a prefered form has a circumferential groove 15 orconstriction, in a plane normal to the axis of the cap and body. The capincludes a cap end 18 with a suitable opening and a capsule indent 24.

The cap 11, in greater detail as seen in FIGURES 2 and 3, has an innerwall 16 and an outer wall 17. On the inner wall 16, opposite the groove15 on the outer wall 17, is a circumferential ridge 19. The ridge 19 hasa generally triangular cross-section defined on the inner surface bybevels 20 and 21 meeting at the apex 22. The closed end 13 is preferablyrounded or hemispherical but the shape is not critical. It desired, thecap end can have other shapes. The inner cap wall 16 proceeding from theopen end 18 to the line 23, which is the shoulder line, has a slightnarrowing diametral taper of the order of 0.010 inch per inch exclusiveof ridge 19 and indent means 24. In 'FIGURE 2 the cap and body parts areshown in the fully locked position Whereas in FIGURE 3 the cap and bodyparts are shown in partly closed or pre-locked position with the openend of the body advanced towards the leading bevel 20 of ridge 19. Thebody has a groove 19a which matches the ridge 19. Groove 19a has aleading bevel 20a and a trailing bevel 21a which join at apex 22a. InFIGURE 2, as indicated, the cap and body have been pressed together fromthe partly closed pre-locked or semi-locked position into the fullyclosed, locked position` In the latter position ridge 19 and body groove19a are in a matching lit or mechanical it as distinguished from afriction iit, with their respective bevels and apexes in closeconformity. In this position the open body end has advanced into the capto a point near or preferably just beyond the shoulder line 23. The bodylike the cap is tapered in the same degree and in the direction from itsopen end to its closed end. The body taper and the body dimensions aresuch as to provide an ample entrance of the body into the cap. The bodytaper and the body dimensions in relation to the taper and dimensions ofthe cap also are such as to provide a relatively distortion-free fit inthe pre-locked position shown in FIGURE 3; the fit between adjacent Wallsurfaces of the cap and body advantageously permits the passage of air.Also, in this position the bevels 20a and 21a and the apex 22a are inclose conformity with the indent flat 24a (FIGURES 5a and 6) and therespective indent slopes 24h. The pre-locked lit in the area of theindent 24 is a mechanical tit as distinguished from a friction lit. Itis substantially distortion-free; the principal points of contact of thecapsule indent 24 with the body groove 19a are at the edges 24d betweenthe indent at 24a and indent slopes 24h. This construction being otherthan a compression lit, makes for increased passage means or air ventmeans 24e so as to permit the escape of compressed air contained withinthe capsule occasioned, for example, by the sudden joining of the bodyand cap parts into locked position. Thus, the release of airadvantageously avoids any tendency of the cap and body to pop apart.Also, the particular constmction of the body groove bevels in relationto the at and slopes of the capsule indent 24 desirably provides auseful centering action so that the axial engagement of the body partwith respect to the cap (i.e., the assembled capsule length) is at alltimes constant. The mentioned construction unexpectedly providesperformance characteristics (in joining, separation, printing, filling,etc.) which are unexcelled by comparison with any prior art capsuleheretofore produced. Thus, there is almost no tendency under theconditions obtaining in capsule manufacture for the pre-locked capsuleparts in accordance with the invention to become separated inadvertentlyor to become joined together farther than intended. While the litbetween the body groove and the capsule indent is substantiallydistortion-free, nevertheless there preferably should be a slightpressure generated at the points of contact sufcient to prevent anysubstantial or excessive rotatioinal movement of the cap and body partswith respect to each other.

It has been found according to the invention that the dimensions andcontour of the capsule indent are a critical feature. In particular, theindent slopes 24b must for purposes of the invention be at a relativelylow angle. This is required, in respect to the dip-molding method, inorder to avoid the excessive formation of air bubbles in the freshlyformed capsule wall. Thus, the slopes 24b in relation to the flat 24a(shown in FIGURE 5 as angle A and angle B) should form an angle of about8-12". An angle of about 10 is preferred whereas slope anglessubstantially more than 12 are associated with the formation ofexcessive numbers of bubbles in the capsule wall portion adhering to thesurfaces of the indent slopes and adjacent portions of the indent at24a. FIGURES 7a, 7b and 7c illustrate how the capsule making fluid movesin relation to an excessively angular pin contour as the pin 25 is beingdipped into the capsule liquid. In FIGURE 7a the capsule liquid 26 isrising upward along the pin and is entering the concavity of the pinmold indent. In FIGURE 7b the liquid has moved farther past the cornerformed by the indent slope and the indent flat without actually wettingthe corner so that the air bubble 27 is formed, In FIGURE '7c thecapsule liquid 26 has moved higher across the capsule indent contourWithout contacting the innermost corner portions of the contour therebycausing air bubbles 27 in these portions. Subsequently in the moldingprocess while the pin bars are being transported, rotated, subjected tothe drying cycle, etc., the air bubbles formed are believed to mergewith the liquid film 26 and to migrate in the film until the film setsup and solidilies, whereupon the air bubbles 27 are physically trappedwithin the capsule wall and particularly with the wall of the capsuleindent 24. Such air bubbles tend to cause an undesirable weakness of thecapsule. In extreme cases, bubble formation results in formation ofholes in the capsule.

The capsule indent 24 of the capsules of the invention must also have arelatively long iiat 24a between the indent slopes 24h. In general, alonger flat is associated with fewer, or smaller, air bubbles. It isfound that in this regard the length of the indent flat separatingslopes 2411 should be greater than about .010 inch and preferably about.020 inch; the width is of the same order and is not particularlycritical, The depth of the capsule indent should be about .004 to .005inch. Shallower capsule indents are less desirable since they give arelatively weak pre-lock, that is, they sometimes fail to properlylocate the body groove for the pre-locked position. On the other hand,where this dimension is deeper the pre-lock tends to be excessive. Thenumber of indents 24 in the capsule is not critical. Two or more indentswith maximum circumferential spacing are preferred, as shown in thedrawing. In general, the ridge and groove dimensions for the cap andbody part, in particular for No. l capsules, are like those specified inthe above-mentioned British and Italian patent specifications.

While gelatin of pharmaceutical grade is a preferred material for themanufacture of the capsules of the invention, other materials havinglike properties can be substituted in whole or in part for gelatin. Itis conventional for capsule mold pins to be made of high-grade stainlesssteel, and it will be understood that the contour of the mold pins usedfor making the capsule parts of the invention can be suitably formed byany conventional means such as milling, grinding or the like. It willalso be understood that the dip-molding process confers the contour ofthe pin precisely to the inner surface of the molded capsule part. Inthis respect the capsule cap parts of the invention which include theridge 19 and the capsule indent 24 can be readily stripped from the`mold pins without difficulty or damage to the capsule part. In thepreferred embodiments shown in the drawing the capsule ridge 19 is shownas a continuous circumferential ridge. Other equivalent ridge shapes canalso be used. For example, the ridge 19 does not need to be continuousbut can comprise spaced discontinuous ridge portions, if desired,separated by wall Iportions having the same circumferential contour ortaper as the greater part of the cap.

While the invention in locking capsules has been described in detail inthe foregoing specification, considerable variation in such detail canbe made, as will be appreciated by those skilled in the art, withoutdeparting from the spirit of the invention.

We claim:

1. A hard shell gelatin pharmaceutical capsule having a cylindrical,telescopically joinable, coaxial cap and body each having a side Wall,an open end and a closed end,

the cap side wall having an inner surface and an outer surface, and alsohaving an axially elongated indent means and a circumferentiallyextending ridge means extending radially inwardly from the inner surfaceof the cap wall,

the body side wall having a circumferentially extending groove matchingthe ridge,

the indent means including two indent slopes separated by an indent at,the slopes in relation to the flat being at an angle of about 8-12" andthe at separating the slopes by a distance greater than about .010 inch,

the capsule cap and body being adapted to be controllably joinedtogether in a semi-lock and also being adapted to be joined together ina full lock located at a pre-determined position of more completejoining beyond the position of semi-lock,

the said full lock being provided by matching contact of the body groovewith the cap ridge means,

the said semi-lock being provided by matching contact of the body groovewith the cap wall indent means, said indent means being axially spacedapart from the ridge means at a suicient distance to accommodate entryof the body into the cap to the semi-lock.

2. A capsule according to claim 1 wherein the semilock is a mechanicallock.

3. A capsule according to claim 1 wherein the body groove and the indentmeans in the semi-lock position are substantially distortion-free andthe matching contact is sutiicient to prevent random change of positionwith respect to relative rotation of the cap and body parts.

`4. A capsule according to claim 1 wherein the matching contact betweenthe body groove and indent means in the semi-lock position defines airvent means for release of compression generated by joining of the capand body parts.

5. A capsule according to claim 1 wherein the indent means comprises aplurality`of indents spaced substantially at equal distance on the capwall circumference.

6. A capsule according to claim 1 wherein the indent means comprises twodiametrically opposed indents.

7. A capsule according to claim 1 wherein the indent means includesindent slopes merging with an indent tiat, the slopes and at extendinginward from the cap wall for a distance suicient to bear upon the bodygroove in the semi-lock position.

8. A capsule according to claim 7 wherein the depth of the indent meansis about .004-.005 inch.

9. A capsule according to claim 7 wherein the angle between the indentslopes and the at is about 10, and the length of the indent flat isabout .020 inch.

10. A capsule according to claim 9 wherein the depth of the indent meansis about .004-.005 inch.

11. A hard shell gelatin pharmaceutical capsule having a cylindrical,telescopically joinable, coaxial cap and body each having a side wall,an open end and a closed end,

the cap side wall having an inner surface and an outer surface, and alsohaving two opposing axially elongated indent means and acircumferentially extending ridge means extending radially inwardly fromthe inner surface of the cap wall,

the body side wall having a circumferentially extending groove matchingthe ridge, each indent means including two indent slopes separated by anindent flat, the slopes in relation to the at being at an angle of about8-12" and the ilat separating the slopes by a distance greater thanabout .010 inch, the capsule cap and body being adapted to becontrollably joined together in a partial lock and also being adapted tobe joined together to provide a full lock located at a position of morecomplete joining beyond the position of partial lock, the said full lockbeing provided by matching contact of the body groove with the cap ridgemeans,

the said partial lock being provided by matching contact of the bodygroove with the two opposing cap wall indent means, said indent meansbeing axially spaced apart from the ridge means at a predetermineddistance to accommodate partial entry of the body into the cap as apartial lock when the body groove is in contact with the indent means.

References Cited UNITED STATES PATENTS 643,005 2/1900 Record 220-601,134,427 4/1915 Ullrich 220-60 2,104,540 1/1938 Hoffman 220-60 X2,718,980 9/1955 Strom 220-60 2,950,813 8/1960 Koones 220--44 X3,399,803 9/1968 Oglevee et al. 220-60 JOSEPH R. LECLAIR, PrimaryExaminer I. R. GARRETT, Assistant Examiner #(ggf UNITED STATES PATENTOFFICE CERTIFICATE OF CORRECTION Patent No. 3.508.678 Dated April 28,1970 Inventor(s) Richard J. Graham, Oscar B. Noren and Ralph E. MottinIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 2, line 7, correct "during finishing, distribution, etc." to read"capsule material, medicament, etc."

Column 2, line 52, correct the spelling of "preferred".

Column 4, line l2, correct "with" to read "within".

SIGNEII AN; HEME!) SEP 8 19m ISEAL) Attest:

Edward Ma metall. Irl

nesting Officer WLLLIAM E. SGHUYLER, Ja.

Commissioner ot Patents 1

